1. Field of the Invention
The present invention relates to an absolute position detection type photoelectric encoder that is devised so as to detect a pseudorandom pattern disposed on a main scale by a plurality of imaging optical systems, and in particular to an absolute position detection type photoelectric encoder that can be easily assembled at a low cost.
2. Description of the Related Art
The present applicant has proposed an absolute position detection type photoelectric encoder, which detects a pseudorandom pattern 200 disposed on a main scale (not illustrated) by means of a plurality of imaging optical systems (five systems in FIG. 1) 110A through 110E as shown in FIG. 1, in Japanese Published Unexamined Patent Application No. 2007-218691 (hereinafter called “Patent Document 1,” and referencing Paragraph Nos. [0035], [0044], FIG. 8 and FIG. 20 hereof).
With the configuration, a plurality of light-receiving array elements 130A through 130E are disposed on the imaging surface of the imaging optical system (for example, lens arrays) 110 in accordance with the imaging ranges of the respective imaging optical systems 110A through 110E.
However, since it is necessary that the positions of the respective imaging optical systems 110A through 110E are exactly matched with the positions of the light-receiving array elements 130A through 130E corresponding thereto, high assembling accuracy is required, which resultantly increases the production cost.